Booster fan



Aug. 13, 1935. A. L. SEARLES BOOSTER FAN Filed Sept. 11, 1933 2Sheets-Sheet l \nven FoY Alva-Q1 L. eafles x I M ATYbme s Aug. 13, 1935.s s 2,011,421

I BOOSTER FAN Filed Sept. 11, 193:5 2 Sheets-Sheet 2 i 9 I V a "1 "llPatented Aug. 13, 1935 iirrso STATES ATE 'orr cr.

8 Claims.

This invention relates to a booster fan adapted to be installed in thelength of a furnace warm air a pipe.

In heating buildings with warm air furnaces,

i warm air pipes lead from the enclosing casing around the radiator,combustion-chamber and firepot' of the furnace, serving to carry thewarmed or heated air to different rooms in the building. It is manytimes desirable that the flow of heated air to a room shall be greaterthan what would normally fiow under the circulation caused by heatingthe air, and thepresent invention is directed to a novel constructionwhich may be installed in the length of a furnace pipe and operated todraw the warm air from the furnace casing and impel it to the room towhich the furnace pipe leads, whereby the room is supplied with agreater amount of heated air than it would otherwise receive. 7

A booster fan of this type or character does not need to be operatingall of the time that the furnace is in operation, and one object orpurpose of the present invention is to provide means for moving the fanto an inoperative position and at the same time automatically cause itscessation of movement. Other objects and purposes are to provide asimple, practical, durable and effective construction of the type noted,and one in which ready access to the fan and to the electric motor whichdrives the same may be had for inspection and repair. And a stillfurther object of the invention is to provide a means for utilizing thebooster fan for circulating cool air, in the warmer months of the year,drawing it from the coolerair of the basement and projecting it into theroom Fig. '2 is an enlarged vertical section taken lengthwise of the-fanunit;

Fig. 3 is a vertical transverse section there-' through. I

Fig. 4 is a side elevationof said fan unit, with parts broken away,illustrating the manner in which the fan and the motor drive thereformay be rendered accessible for inspection or repair.

Fig. 5 is a rear elevation of the fan and its motor and the Venturihousing in which it is located,

and

' Fig. 6 is a fragmentary vertical elevation showing the manner in whichan electricswitch for cutting the current tothe electric motor. isautomatically operated upon turning the fan to a lower inoperativeposition. v

Like reference characters refer to like parts in the diiierent figuresof the drawings. 1

The furnace may be of any conventional'cone struction,.,having anenclosing casing I from which a plurality of warm air pipes 2 are ledlaterally and upwardly, each to a' register 3 in-a room of the house whichis to be heatedby the,

furnace, the register being above the floorifi as shown, though the typeor character of register,-

whether it be vertical or horizontal, is of no importanceinsofar as thepresent invention is con-' cerned.

The booster fan unit of my invention includes inits construction ahollow casing of rectangular parallelepiped form having a top 5,parallel sides 6 and 'i andparallel front and'back B and 9, from each ofthe latter of which a'short pipe sleeve 1 0, having the same diameter asthe diameter of the warm air pipe 2, projects. A-section of the warm airpipe 2 may be removed and the casing de scribed inserted in its placewith the ends of the parts i!) in substantially abutting relationwith"the-ends or" the pipes 2. The apparatus is ,se-, cured in place byclamping bands ll which pass around and overlap the adjacent endportions of the parts 2 and i0 as shown in- Figs. 1 and 2. As shown inFig. 2, these bands H are Welded to the sleeves Hi only'near theirbottomportions, thus permitting the sleeves to be bent or sprung outwardlyeasily during the installation of the apparatus.

The lower side of this casing isclosed by a bottom 12 hinged at one sideby means of hinges 83 whereby the bottom maybe moved to a closedposition and held therein by suitable latch means,"

or it may be turned to open position as shown in Fig. 4. It will benoted that the central axis of the pipes 2 and It is located above the'central horizontal plane of the casing described so that there is aconsiderable portion of the chamber below the lower sides of the pipes 2and I 0, the purpose of which will be hereafter described;

a A horizontal rock shaft Mextends throughthe casing adjacent the rearside 9 and below the lower side of the pipes 2.

a crank arm l5 therefor. f The fan'unit per se At one end, adjacent the:side figitis turned at right angles making is mounted on the rock shaft14 within the hollow casing described. One end l6 of a bar I! is bent orformed into a clasping roll or eye around the rock shaft [4 andpermanently secured thereto. The bar I! extends from the rock shaft l4and is permanently secured to a second bar l8 which axis of the pipes 2and Ill so that air may pass freely from the furnace casing through thefirst section of the pipe 2 and thence through'the Venturi housing tothechamber of the casing described, and therefrom to the other section 2which leads to the register'3.

An electric motor is carried on the bar I8 and on its'shaft a fan 22is'se'cured the diameter of which isslightly lessthan the cylindricalportion 20 of the Venturi structure. It has been found essentialfor bestresults that the plane of rotation of the fanl 22 be located'coincidentwith the end of; the frustro conical section l9 of the Venturi structureor in other words that the plane of rotation of the fan and the plane inwhich'the cylindrical portion 20 and the frustro conical portion I9 joinbe coincident. This location of the fan relative to the Venturistructure reduces recirculation of the air to a minimum and causes thefan'to circulate the air most directly parallel with its axis. l V vCircuit wires 23 connect with the motor winding and pass therefromthrough an opening in the conical section I9 of the Venturi housing, andthence through the side 6 of the casing to a switch box 24 which isinterposed in the length of the wires 23 and secured for support to saidside 6. Normally the switch within the switch-box closes automaticallyby spring action.

An operating finger 25 for the switch extends outwardly beyond a sideof, the switch box 24 into the pathrof movementof the crank rod orhandle l5. By turning thepart from its upper nearly vertical position,as shown in Fig. 1, to its lower nearly horizontal position as shown indotted lines in Fig.1, the part 15 engages and movesthe finger 25 andautomatically operates the switch to break the circuit and stop themotor from driving the'fan. V

It is evident thatby reason of the connection of the barfll'lto the rockshaft. M a turning of ,the' crank handle l5 from one position to the thelower chamber space of the casing below the 1 lower sideof the pipesections Zand It). In

such'position the fan is automatically'stopped andair may pass from thefurnace casing, I

through the pipe 2 and thence to the room, the

same vasthough the booster fan construction or: my invention. was notinstalled in the length'off 1 1 the pipe.

may be understood that the device may'also be installed in an inclinedpipe. When installed in *1 an inclined 'pipetheVenturi structure,combined with the motor and fanlocated in operative position, will notbe sufficiently inclined so that the preponderanceof weight relative tothe supporting shaft I4 will retain the parts by gravity in.

such position but the center of gravity will be so positioned relativeto the supporting axis as to cause downward movement of the fanstructure at all times when it is free to so move;

When the device is installed in a substantially horizontal pipe, asillustrated, it will be seen that gravity tends to move the Venturi andfan and.

motor structure to inoperative position. A chain '21 is provided toraise it and maintain it in operative position and when the chain isreleased the device will move by gravity to its operative posi tion. Thechain 21 engages holding 'means'28 as clearly shown in Fig. 1.

Thus the device may readily be operated by a person in the room to beheated by manipulating the chain 21 and when the parts are moved tooperative position the crank arm l5 releases the lever 25 of the switch24 permitting the switch to close and causing the fan motor to operatethe fan which operation will continue so long as the device is in itsraised operative position but when lowered by operation or the chainsthe crank arm I5 will reengage the switch lever andibreak,

the fan circuit causing the fan to cease operation and at the same timethe fan and Venturi structurewill lie within the lowerpart of the casing5 as illustrated in dotted lines inF ig; 2

where it will not interfere with natural circulascribed so that theVenturi housing for thefan" may be properly supported when in, itsinopers ative position as shown in Fig. 2. 'It'is desirable at timesthatthe fan and the housing therefor be lowered to a still lower positionthan that shown in Fig. 2, that is, projected partially outside of thecasing. It will be noted that two'c'ot ter pins spaced apart from eachother, ex-

tend through one end portion of the rock shaft [4 (see Fig. 3). When itis desired to lower the-. 1 fan and its housing to the'positionshowninposition, as in Fig. 4, the fan and its motor and housing around it maybe lowered through the open lower side of the casing the bottoml2ha'ving been turned to the'position in Fig. 4, Where- .upon readyexamination and'access to the fan and .its motor may be had. The housingsection l9 is'formed at one side"; as at 19a, to permit the longitudinalmovement of shaft i4 and the attached parts. f

From the fore'goingdescription it is evident that a very practical andserviceable booster'fan con-' The ease with which the fan unit isdropped out of the air course passing through the furnace pipe so as notto obstruct thesame, coupled with the automatic stopping of the fan is avery desirable and practical feature of the present invention. TheVenturi construction of the immediate fan housing aids very materiallyto the efficiency of the. fan, obviating back air currents and eddies. 1

This construction, while primarily of use in boosting the flow of heatedair from a furnace to a room, is also very useful in the warmer monthswhen the furnace is not operating for circulating cooler air from thebasement to the rooms. This can be done by merely dropping the bottom I!to the dotted line position shown in Fig. 1, leaving the fan in itsoperative position, whereupon the fan will serve to siphon cool air fromthe basement. It is also conceived that the device may be installed andpractically utilized in the cold air return pipe of the heating systemand when so used it has the effect of increasing the air circulation byblowing in a direction toward the furnace jacket which results ingreater heating efficiency of the furnace. The installation of the unitis simple and easy, consisting merely of removing a section of the warmair pipe 2, placing the unit in the space formerly occupied by saidsection and clamping it in place by use of the clamping bands H.

The invention is defined in the appended claims and is to be consideredcomprehensive of all forms of structure coming within their scope.

I claim:

1. A construction of the class described adapted to be interposed in thelength of a' furnace warm air pipe comprising, a casing having a top,vertical sides and a vertical front and back, a bottom hingedlyconnected to said casing to close the lower side thereof, sleevesconnected to the front and back and extending therefrom in axialalinement, a horizontal rock shaft passing through the sides of saidcasing, a Venturi fan housing secured to said rock shaft and comprisingafrustro-conical section and a short cylindrical section, an electricmotor mounted within said housing, a fan driven by said motor within thehousing, and a releasable latch for the housing carried by the front ofsaid casing, whereby the housing with the attached motor and fan may beturned to a lower horizontal position and supported by said latch or maybe turned to a still lower position and projected partially outside ofsaid casing on release of the latch and opening said bottom, asspecified. V

2. A construction containing the elements in combination defined inclaim 1, combined with manually operable means for turning the fan,motor and housing to upper operative or lower inoperative positions, andmeans for automatically stopping the motor when turned to lower positionand for starting it when turned to upper position.

3. A construction of the class described adapted to be interposed in thelength of a furnace warm air pipe comprising, a casing having a bottomhingedly connected to said casing to close the lower sidethereof, ahorizontal rock shaft passing through said casing, a Venturi fan housingsecured to said rock shaft and comprising a frustro-conical section anda short cylindrical section, an electric motor mounted within saidhousing, a fan driven by said motor within the housing, and a releasablelatch for the housing carried by the said casing, whereby the housingwith the attached motor and fan maybe turned to a lower horizontalposition and supported by said latch or may be turned to a still lowerposition and projected partially outside of said casing on :a

release of the latch and opening said bottom, as

specified.

4. In combination with a furnacepipe adapted to extend from a furnacecasing, of a casing having a lateral extension and an opening leadinginto said lateral extension, a cover for saidopening, said casing being.interposed in the length of the pipe, a fanmounted for change ofposition and provided with supporting means for one position in which itis located in alinement with the furnace pipe, another in which it is inthe lateral extension and below the lower side of said pipe, and a thirdin which it is swung partly through the opening in said casing, andmeansfor manually moving the fan to any of said positions.

5. A construction of the class described adapted to be interposed in thelength of a furnace 1 pipe comprising, a casing having a bottom hingedlyconnected to said casing to close the lower side thereof, a horizontalrock shaft passing through said casing, a housing secured to said rockshaft and open at both ends, an electric motor mounted on said housing,a fan driven by said motor Within the housing, and releasable means forthe housing carried by the said casing, whereby the housing with theattached motor and fan may be turned to a lower horizontal position andsupported by said releasable means or may be turned to a still lowerposition and projected partially outside of said casing on release ofthe releasable means and opening said bottom, as specified.

6. In a construction of the classdescribed, an enclosing casing providedwith ducts at opposite sides for connecting the same to sections of afurnace warm air pipe, thereby disposing the easing in the length ofsaid pipe, a rock shaft slidably extending through the casing andadapted for axial movement to two predetermined positions, an electricmotor and a fan driven thereby carried on and supported by the rockshaft whereby it may be positioned substantially between the said ductsand substantially at right angles to the axis of one duct and also swungdownwardly, an arm extending from the rock shaft, an electric circuitfor the motor, a switch in said circuit, and 1 to be interposed in thelength of a furnace pipe comprising, a casing having a bottom hingedlyconnected to said casing to close the lower side thereof, a horizontalrock shaft passing through said casing, a housing secured to said rockshaft and open at both ends, an electric motor mounted on said housing,a fan driven by said motor within the housing, and means for supportingthe fan in alinement with the axis of the furnace pipe, said housingwith the attached motor and fan being rotatable to a position whereinthey are projected partially outside of said casing when the said bottomis opened.

8. 'A construction of the class described adapted to 'be interposed inthe length of a furnacepipe comprising, a casing-,scylindrical sleevessecured to and extending from said casing 'in substantially axialalinement, said cylindrical sleeves being located near the top of thecasing, a pivoted rock shaft passing through the said casing below thelowermost point of the cylindrical sleeves, a fan, an electric motorconnected to and driving the fan, and a support for the electric motorconnected with said rock shaft, said rock shaft being movable through anarc of substantially 90, whereby said shaft may be turned to positionthe 'fan in alinement with said sleeves or moved to a unobstructedpassage is haddirectly through the casing, releasable means forpositively maintaining the fan in alinement with said sleeves, means forsupporting the fan in its lower positionand door means in the casingadjacent the fan when the'fan is in its lower position, said door meansbeing capable of being' opened regardless of the position of the saidfan, and'said fan being operable in its lower position to induce a flowof air into the pipe when said door is opened.

- l ALVAH L. SEARLES.

